The Effect of Supplied Electrical Energy on Fuel Spray Using High-Voltage Electric Discharge

Three fractions of tobacco waste (scrap, dust and midrib) were subjected to a high voltage electric discharge (HVED) assisted extraction procedure under different experimental conditions: solvent:solid ratio (300, 500, 700 mL/g), frequency (40, 70, 100 Hz) and treatment time (15, 30, 45 min), in order to study the influence of these conditions on the content of chlorogenic acid. The content of chlorogenic acid ranged from 1.54 to 3.66 mg/100 g for scrap, from 1.90 to 2.97 mg/100 g for dust, and from 2.30 to 3.38 mg/100 g for midrib extract, showing a strong dependence on the applied process parameters. The temperature change and the change in pH and electrical conductivity of the extracts after high voltage discharge treatment were also observed. The studied process parameters showed a statistically significant effect on the chemical and physical properties of the extracts from tobacco waste as well as on the content of chlorogenic acid, indicating the potential of HVED assisted processes in the separation of chlorogenic acid from tobacco industry waste. Multiple regression analysis was used to fit the results for the chlorogenic acid to a second order polynomial equation and the optimum conditions were determined.

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Direct conversion of CO2laser energy to high-voltage electrical energy

IEEE Journal of Quantum Electronics ◽

10.1109/jqe.1977.1069606 ◽

1977 ◽

Vol 13 (9) ◽

pp. 908-908

Author(s):

W. Silfvast ◽

L. Szeto

Keyword(s):

High Voltage ◽

Electrical Energy ◽

Direct Conversion

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Multiple Rock Breakdown in Electrodischarge Technology

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.712.55 ◽

2016 ◽

Vol 712 ◽

pp. 55-59

Author(s):

Vladislav M. Vazhov ◽

Sergey Y. Datskevitch ◽

Mikhail Y. Zhurkov ◽

Vasily M. Muratov ◽

Arild Rødland

Keyword(s):

Electric Discharge ◽

High Voltage ◽

Voltage Pulse ◽

Rock Fracture ◽

High Voltage Pulse ◽

Electric Strength ◽

Drilling Process ◽

Drill Bit ◽

Research Outcomes ◽

Experimental Technology

The article covers the research of the electric strength and fracture of rocks that are undergone multiple breakdowns generated by electric discharge rock fracture and drilling technologies. The research outcomes allow proposing an experimental technology able to determine operating high voltage pulse values in the electric discharge drilling process where one should take into account such factors as the rock re-crushing and the drill bit shift cyclicity.

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Operation Modes of HV/MV Substations

Scientific Journal of Riga Technical University Power and Electrical Engineering ◽

10.2478/v10144-009-0018-y ◽

2009 ◽

Vol 25 (25) ◽

pp. 81-86

Author(s):

Josifs Survilo ◽

Antons Kutjuns

Keyword(s):

High Voltage ◽

Low Voltage ◽

Warm Season ◽

Electrical Energy ◽

Cold Season ◽

Power Losses ◽

Medium Voltage ◽

The Third ◽

Operation Modes ◽

Mode 3

Operation Modes of HV/MV SubstationsA distribution network consists of high voltage grid, medium voltage grid, and low voltage grid. Medium voltage grid is connected to high voltage grid via substations with HV/MV transformers. The substation may contain one, mostly two but sometimes even more transformers. Out of reliability and expenditure considerations the two transformer option prevail over others mentioned. For two transformer substation, there may be made choice out of several operation modes: 1) two (small) transformers, with rated power each over 0.7 of maximum substation load, permanently in operation; 2) one (big) transformer, with rated power over maximum substation load, permanently in operation and small transformer in constant cold reserve; 3) big transformer in operation in cold season, small transformer-in warm one. Considering transformer load losses and no load losses and observing transformer loading factor β it can be said that the mode 1) is less advantageous. The least power losses has the mode 3). There may be singled out yet three extra modes of two transformer substations: 4) two big transformers in permanent operation; 5) one big transformer permanently in operation and one such transformer in cold reserve; 6) two small transformers in operation in cold season of the year, in warm season-one small transformer on duty. At present mostly two transformers of equal power each are installed on substations and in operation is one of them, hence extra mode 5). When one transformer becomes faulty, it can be changed for smaller one and the third operation mode can be practiced. Extra mode 4) is unpractical in all aspects. The mode 6) has greater losses than the mode 3) and is not considered in detail. To prove the advantage of the third mode in sense of power losses, the notion of effective utilization time of power losses was introduced and it was proven that relative value of this quantity diminishes with loading factor β. The use of advantageous substation option would make it possible to save notable amount of electrical energy but smaller transformer lifetime of this option must be taken into account as well.

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Calculations, norming and reducing of electrical energy losses in city electrical networks

Proceedings of the higher educational institutions ENERGY SECTOR PROBLEMS ◽

10.30724/1998-9903-2019-21-3-46-54 ◽

2019 ◽

Vol 21 (3) ◽

pp. 46-54

Author(s):

A. V. Lykin ◽

E. A. Utkin

Keyword(s):

High Voltage ◽

Power Transmission ◽

Low Voltage ◽

Demand Curve ◽

Electrical Energy ◽

Electrical Network ◽

Energy Losses ◽

Capital Investments ◽

Electrical Networks

The article considers the feasibility of changing the structure of a distribution electrical network by transferring points of electricity transformation as close to consumers as possible. This approach is based on installation of pole-mounted transformer substations (PMTS) near consumer groups and changes the topology of the electrical network. At the same time, for groups of consumers, the configuration of sections of the low-voltage network, including service drops, changes. The efficiency of approaching transformer substations to consumers was estimated by the reduction in electrical energy losses due to the expansion of the high-voltage network. The calculation of electrical losses was carried out according to twenty-four hour consumer demand curve. To estimate the power losses in each section of the electrical network of high and low voltage, the calculated expressions were obtained. For the considered example, the electrical energy losses in the whole network with a modified topology is reduced by about two times, while in a high-voltage network with the same transmitted power, the losses are reduced to a practically insignificant level, and in installed PMTS transformers they increase mainly due to the rise in total idle losses. The payback period of additional capital investments in option with modified topology will be significantly greater if payback is assessed only by saving losses cost. Consequently, the determination of the feasibility of applying this approach should be carried out taking into account such factors as increasing the reliability of electricity supply, improving the quality of electricity, and increasing the power transmission capacity of the main part of electrical network.

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Investigation of Ways to Reduce the Inrush Current when Starting High-Voltage Motors

Bulletin of the South Ural State University series Power Engineering ◽

10.14529/power210210 ◽

2021 ◽

Vol 21 (2) ◽

pp. 94-104

Keyword(s):

High Voltage ◽

High Power ◽

Oil And Gas ◽

Supply Voltage ◽

Electrical Energy ◽

Oil And Gas Industry ◽

Energy System ◽

Energy Performance ◽

Inrush Current ◽

Industrial Enterprises

The operation of high-power industrial electrical installations, particularly in metallurgy and the oil and gas industry, is associated with complex technological processes that require increased attention to the equipment used, as such equipment is used in complex and dangerous production conditions and in continuous operation facilities. High-voltage air and gas compressors are objects with increased electrical energy consumption and have significant starting currents. These circumstances affect both the shape of the supply voltage and the state of the energy system in general. Currently, the development of methods for limiting inrush currents is an urgent task for objects used in industrial enterprises. Introducing a compressor into the technological process is sometimes requires prior coordination of its start with the equipment in operation, especially that with a high power consumption. The paper studies the existing control system as well as ways to upgrade the system to improve its energy performance.

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Selecting the Switching Frequency of the 6500 V IGBT High Voltage DC Converter

Elektrichestvo ◽

10.24160/0013-5380-2021-8-21-27 ◽

2021 ◽

pp. 21-27

Author(s):

Sergey I. Volskiy ◽

◽

Yuri Yu. SKOROKHOD ◽

Nikolay Echkilev ◽

◽

...

Keyword(s):

High Voltage ◽

High Frequency ◽

Electrical Energy ◽

Input Voltage ◽

Switching Frequency ◽

Energy Transformation ◽

Power Losses ◽

Voltage Converter ◽

Passenger Cars ◽

Power Circuit

The high-voltage converter with the input voltage of 3000 V DC is considered for use as a power supply for auxiliary circuits of commuter electric trains and passenger cars that are used on Russian railways. The limitations on the use of semiconductor devices in converters with an input voltage of 3000 V are shown. The power electrical circuits of the input units of the considered high-voltage converters are shown when using of 1700 and 6500 V IGBT. The expressions for calculating the power losses and the algorithm for selecting the switching frequency of 6500 in IGBT are given. This article is of interest to developers of high-voltage DC converters with an input voltage of 3000 V and higher, which choose IGBT for the power circuit of input units with using the high frequency principle of the electrical energy transformation.

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Idejno rešenje regionalnog Data Centra kod Beograda napajanog iz obnovljivih izvora energije

Energija, Ekonomija, Ekologija ◽

10.46793/eee21-3.10v ◽

2021 ◽

Vol 23 (3) ◽

pp. 10-17

Author(s):

Ivan Vujović ◽

Željko Đurišić ◽

Keyword(s):

High Voltage ◽

Power Supply ◽

Wind Farm ◽

Low Voltage ◽

Power Transformer ◽

Renewable Energy Sources ◽

Geographical Location ◽

Electrical Energy ◽

Economic Benefits ◽

Infrastructure Development

Telecommunications and computer equipment centralisation trends for the purpose of achieving economic benefits, usage of technological innovations and new technical solutions implementation leads to the requirements for building bigger Data Centres (DCs). An increase in the size of the DC facility i.e. the number of racks inside occupied with equipment and the number of devices that enables the proper functioning of that equipment leads to necessarily power energy requirements increasing for power supply. For the DCs that require a large amount of energy, the building of their own, usually renewable energy sources (RES) is cost-effective. In such a caser, RES are primary and Power System (PS) is secondary and redundant power source. A concept of a DC primary powered from RES is presented in this paper. Generated electrical energy in RES is transmitted in PS through high voltage switch-gears (SGs) while DC is power supplied from PS through low voltage, medium voltage and high voltage SG-s. For the purpose of realisation of such facility, it is necessary to enable adequate conditions related to geographical location, physical access to the facility, possibility of connecting to the PS and possibility of connecting to the telecommunications centres. Based on carried out researches related to RESs potential, available roads, power supply infrastructure and telecommunication infrastructure, development conditions for DC on location near to Belgrade, close to power transformer station „Belgrade 20“ are analysed in this paper. From the aspect of DC power supply, proposed solution includes wind farm, solar plant and landfill gas power plant, as well as related SGs. Telecommunication connections from DC to the PS and other important telecommunication centres are provided. These connections are realised through optical cables placed next to the electrical lines and cables, and, when that is not possible, placed independently in the ground. The design of the DC interior is given and calculations of the required electrical energy for the power supply of the equipment and devices in the facility are performed. Based on calculation results, capacity calculation of the RES and calculation of SGs are performed. Design of the interior optical connections inside DC is also given. A General assessment of the investment and economics of building such DC are given at the end of the paper.

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